The present disclosure relates to nondestructive component inspection and, more particularly, to a nondestructive thermoacoustic imagery system for prognostics and health management, preventative maintenance, and repair of gas turbine engine parts.
Manufactured components may incur defects or imperfections during manufacturing or suffer wear and defect during operation. These components, therefore, are episodically or periodically inspected. Some types of defects consist of delamination or improper bonding of composite structures. These types of defects may be detected by thermoacoustic techniques (also known as vibroacoustic, vibrothermography, thermosonic, or sonic infrared techniques) wherein vibration of the component induces localized heating at defect locations. The heating is detected by an infrared camera. Typically, the imagery is reviewed manually for the detection of defects. These reviews are tedious, time consuming, imprecise, and may be error prone.
More recently, automated statistical analysis has been performed for crack detection using rapid exterior heating of a component and infrared imaging. For instance, pulsed thermography, where a very short intense flash of light heats a component, has been used to show thermal conductivity of a coating. These methods, however, require external heating of the component, which may not be applicable to composite material components.